The two rivers merge with the Alabama near Coffeeville to form the Mobile River.
It in turn empties into Mobile Bay on the Gulf of Mexico. The rugged terrain in
the upper reaches of the Black Warrior is characterized by high ridges and deep
river gorges. The upper Tombigbee basin is hilly but below the fall line it is
low and gently rolling like the coastal region of the Black Warrior.
The Black Warrior basin has abundant natural resources and is one of the most
highly industrialized areas in the Southeast. The Tombigbee basin is primarily
agricultural.
The two rivers have played a vital part in development of their basins. First
explorers, then traders and settlers used the rivers as water highways. The
settlement of the town of Mobile was successful largely because of its ideal
location to serve as a port of the inland river system.
In the nineteenth century, cultivation of cotton and invention of the
paddlewheel steamboat stimulated trade on the rivers. But hazards such as
sandbars, fallen trees and shoals impeded navigation. In 1875, the first plans
to improve the rivers for navigation were approved.
Between 1895 and 1915, a system of 17 locks and dams was constructed between
Mobile and Birmingham. In those days, waterway construction was a slow and
laborious task. Dams were built by hand of stone and mortar. Locks were walled
with stone-filled timber cribs, and hauling was done by mule-power.
The original locks and dams were built to provide a six-foot-deep channel,
adequate for the steam-powered tow boats and packets of the era. The Corps
undertook a program to modernize the system in 1937. The 17 low-lift locks were
replaced by six high-lift locks, capable of expediting present-day towboats and
barges. The locks vary in maximum lift from 22 to 69 feet. The nine-foot
navigation channel is maintained to a width of 200 feet. Tows of up to eight
standard barges can be accommodated at all locks.
The waterway is now approximately 457 miles long. All of the original locks
and dams have been replaced except for John Hollis Bankhead Dam on the Black
Warrior near Birmingham. The structures at Bankhead were the last of the
original locks and dams built on the system. Bankhead dam has been modernized
and a new lock has been constructed to make it comparable in efficiency to the
other locks and dams in the system.
|